Tension device for shears.



c. w. SPRAGUE. TENSION DEVICE FOR SHEABS.

APPLICATION FILED AUG. 31. 190B.

Patented Feb. 23, 1909.

Wihwmea QWFW' atmncq CLARENCE W. SPRAGUE, OF PHILADELPHIA, PENNSYLVANIA.

TENSION DEVICE FOR SHEARS.

Specification of Letters Patent.

Patented Feb. 23, 1909.

Application filed August 31, 1908. Serial No. 451,065.

To all whom it may concern:

Be it known that I, CLARENCE \V. SPRAGUE, a citizen of the UnitedStates, residing at Philadelphia, in the county of Philadelphia andState of Pennsylvania, have invented certain new and useful Improvementsin 'lension Devices for Shears, of which the following is aspecification, reference being had therein to the accompanying drawing.

My invention relates to improvements in tension devices for shears.

The object of my invention is to provide a tension device for shears inwhich an even tension may be maintained between the two cutting bladesand at the same time doing away with the usual harshness in ordinarytension devices now in use.

Another object of my invention is to provide a simple, cheap andeffective tension device which can be readily attached to any form ofshears now in use, and in which the parts can be readily replaced whenthey become Worn.

In the accompanying drawings, Figure 1, is a side elevation of a pair ofshears showing my tension device applied thereto. Fig. 2, is a vertical,longitudinal, sectional view of Fig. 1. Fig. 3, is a detached,perspective view of the several parts forming my tension device, andwhich may be applied to any form of shears. Fig. 1, is a sectional viewof a modification. Fig. 5, is a detached, perspective View of the cupand washers shown in the modification.

Referring now to the drawings, 1 represents one blade of a pair ofshears, and 2 the other blade which are pivoted together in the usualmanner by the pivot 3, all of which is of the ordinary form of shearsand is simply shown to show the application of applicants tension deviceto the ordinary shears.

The blade 1 adjacent the pivot 3, and in rear thereof, is provided withan opening 1- extending therethrough, and which could be made during themanufacture of the shears. This opening could be drilled in thecompleted blade, thus making the device applicable to any ordinaryshears. As before stated, the opening 41 is adjacent the pivot 3 so thatthe blade 2 when swinging on the pivot Will at all times cover orpartially.

l i i i l i thickness of the blade. The inner sleeve is provided withthe laterally extending flange 7 which rests within the enlarged portionof the opening, and the inner end of the sleeve or bushing is flush withthe inner edge 8 of the blade 1, so that the same will not interferewith the movement of the blades upon each other.

The sleeve or bushing (S has at its inner end an enlarged opening 9ending in the upper smaller opening 10 which is internallyscrew-tln'eaded. Extending through threaded opening 10 is a thumb-screw11 having the enlarged head 12 by means of which the screw can bereadily moved in or out, as desired. Within the said enlarged opening isa washer 12 which is made of any desired metal, and against which theinner end. of the screw 11 is adapted to bear. Vithin said enlargedopening below the washer 12, is a second washer 13 composed of rubber orother elastic material, and below this elastic washer is still anothermetal washer 14, the lower face of which is slightly convexed and groundsmooth to allow 1t to freely pass over the upper face 15 of the lowerblade 2.

The set screw bearing upon the washer 12 and the elastic washer 13 beingbetween said washer and the washer 14, it will be seen that the washer141 does not have a positive unyielding contact with the lower blades asthose now in use, and the superposed elastic washer revents the thumbscrew from being worzed loose by the movement of the blade against thedisk 14 like those in which the set screw directly engages the frictiondisk. This produces a more effective tension device, and also provides adevice which is wholly carried by the sleeve or bushing, and which formsa more effective device. The sleeve 6 may be, if desired, welded in theopening which forms a more perfect and even inner face when ground downsmooth with the lower face of. the blade 1, although it can be simplyapplied as shown and a set screw holding it, owing to the pressurethereon through the washers. The set screw being in rear of the pivot,it

will be seen by screwing the same down wardly the outer cutter edgeswill be brought together.

In Figs. 4 and 5, instead of using a washer 14, I use a cup-shapedmember 14 which is of a depth slightly greater than the washers 12' and13, and in which said washers loosely fit. The cup-shaped member is ofa'diameter slightly less than the opening 9, so that there will be nopossibility of any binding thereof within the opening. This cupshapedmember not only provides a carrying means for the washers 12' an d.13,but also has the advantage over the washer 14: of preventing the samefrom. accidentally slippingout-of the opening 9 shouldthe screw 3 workloose, which might. possibly be the case with the washer 14. Thecup-shaped member has all other advantages of the washer 14.

Having thus described my invention, what I claim, and desire to secureby Letters Patent, is

'1. The combination with a pair of shears, of a set screw extendingthrough one blade of the shears, a washer against which said setscrew-bears, an elastic washer below the first mentioned washer, and athird washer below the elastic washer and adapted to bear against theupper face of the other blade.

2. The combination with a pair ofshears, of. a bushing set within oneblade and flush with the lower face thereof, of a set screw within saidbushing, a metal washer within the bushing and against which the setscrew bears, an elastic washer below said metal washer, and ametalwasher. below the clastic washer andbearing against the upper face ofthe other blade of the shears.

3. ,The combination with .a pair of. shears, of a bushing set within oneblade and-flush withthe inner face thereof, said bushing havingcontracted outer end, a set screw screwed into said contracted outerend, a washer within said bushing and against which the setv screwbears, an elastic washer within the bushing below the first-mentionedwasher, and a washer below the elastic washer and adapted to. engage theinner face of the other blade of the shears.

4. Theccombination with a pair of shears, one blade having an openingtherethrough on the inside of the pivot, said blade having its innerface provided with an annular re cess surrounding said opening, abushing within the opening and having a flange resting in the annularrecess to prevent the outward 'movement of the bushing, saidbushinghaving its flange flush with the in ner face of the blade and itsouter end eX- tending a distance beyond the outer face of the blade, aset screw screwed through the outer extended 'end, said bushing havingan enlarged bore at its inner end, a metal washer within the bushing andagainst which the set screw bears, an elastic washer below the metal.washer, and a second metal washer below the elastic washer and itslower face slightlyconvexed whichis adapted to bear upon the inner faceof the other blade, said bushing being so positioned that the otherblade at all times coversthe same and retains the washer therein.

The combination with a pair of shears, of a set screw extending throughone blade .of the shears, a cup-shaped member loosely mounted in theblade below the set screw and adapted to engage the upper face of theother blade, .an elastic member within the cup-shaped member, a washerwithin the cup-shaped member and bearing against the elastic member, andagainst which the set screw is adapted to bear.

6. The combination with a pair of shears, one blade having an openingtherethrough on the inside of the pivot,,said blade having its innerface provided with an annular recess surrounding the said opening, a.bushing within said opening and having a flange restingin said annularrecess, to prevent the outward movement of the bushing, saidbushinghaving its flange flush with the inner face of the blade and itsouter end eX- tending a distance beyond the outer face of the blade, aset screw screwed through the outerembedded end, a cup-shaped memberloosely mounted in the lower end of the bushing and having its closedend bearing againstthe inner face of the other blade, a flexible memberwithin the lower end of the cup-shaped member, and a metal washer withinthe cup-shaped member and. against which the set screw bears.

In testimony whereof I aflix my signature in presence of two witnesses.

CLARENCE W. SPRAGUE.

Witnesses A. I. MILLIGAN, THOMAS DUNCAN.

